In these images A and B the anterior view of the intact parietal (fibrous) pericardial sac is shown. The attachment of the fibrous sac to the diaphragm is seen at the base. Abundant epipericardial fat is conspicuously present at the pericardial-diaphragm junction. The mediastinal pleura invest the lateral portion of fibrous pericardium. The anterior reflections of the mediastinal pleura are indicated by the white arrowheads. The space between the arrowheads corresponds to the attachment of the pericardium to the posterior surface of the sternum. Superiorly, the left innominate vein is seen merging with the superior vena cava. The arterial branches of the aortic arch are just dorsal to the innominate vein.

C and D. The anterior portion of the pericardial sac (fibrous pericardium) has been removed to show the heart and great vessels in anatomic position. It distinctly shows how the proximal segments of the great arteries are intrapericardial. A that point, there is fusion of the adventitia of the great vessels with the fibrous pericardium.